|Witnesses said pro-Saleh supporters in plain clothes opened fire on the unarmed protesters [Reuters]
Five protesters have been killed in the Yemeni capital, Sanaa, witnesses and medics say.
The demonstrators had been protesting in the centre of the city against a power transfer deal that promises President Ali Abdullah Saleh immunity from prosecution.
Government loyalists dressed in plain clothes reportedly opened fire on the protesters from roof tops and moving cars.
Thirty-three people were injured, according to Al Jazeera's special correspondent, who reported from a makeshift hospital in a nearby mosque.
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"I can see five corpses lined up in the corner of the room. I just spoke to a medic who said 33 others have been wounded. All have bullet wounds," he said.
Protesters in the Change Square, the epicentre of anti-government rallies since February, had gathered for a mass demonstration against the promises of immunity granted under the agreement with the parliamentary opposition which Saleh signed in the Saudi capital, Riyadh, on Wednesday.
The protesters also chanted slogans against the Common Forum parliamentary opposition bloc led by the al-Islah (reform) party.
"Common Forum, Islah, leave after the assailant," they shouted, referring to Saleh, who is expected to go straight from Riyadh to New York for medical treatment.
The deal, brokered by the Gulf Co-operation Council, will see Saleh leave office in 30 days, making way for Abdrabuh Mansur Hadi, the Yemeni vice-president, to negotiate a power transfer with the opposition.
As part of the deal Saleh will retain the honorary title of president, yet his deputy is expected to form and preside over a national unity government before presidential elections take place within 90 days.
Source: Al Jazeera and agencies